Risk is a strategyboard game produced by Parker Brothers (now a division of Hasbro). It was invented by French film directorAlbert Lamorisse and originally released in 1957 as La Conquête du Monde ("The Conquest of the World") in France. It was later bought by Parker Brothers and released in 1959 with some modifications to the rules as Risk: The Continental Game, then as Risk: The Game of Global Domination.[1]

Risk is a turn-based game for two to six players. The standard version is played on a board depicting a political map of the Earth, divided into forty-two territories, which are grouped into six continents. The object of the game is to occupy every territory on the board and in doing so, eliminate the other players.[2] Players control armies with which they attempt to capture territories from other players, with results determined by dice rolls.

Eight 'territory cards' from the 1963 UK set and the same from 1980 UK set. The latter were more accurate maps (northern 'Ukraine' and Greece in 'Southern Europe' are more lifelike) and the cards were better quality of material.

Each Risk game comes with a number of different colored tokens denoting troops (originally, one set each of black, blue, green, pink, red and yellow). In the first editions, the playing pieces were wooden cubes representing one troop each and a few rounded triangular prisms representing ten troops each, but in later versions of the game these pieces were molded of plastic to reduce costs. In the 1980s, these were changed to pieces shaped into the Roman numerals I, III, V, and X. The 1993 edition introduced plastic infantry tokens (representing a single unit), cavalry (representing five units), and artillery (representing ten units). The 40th Anniversary Collector's Edition contained the same troop pieces but made of metal rather than plastic. In the 2005 "bookcase" edition, playing pieces are once again wooden cubes. These token types are purely a convention for ease of representing a specific army size. If a player runs out of army pieces during the game, another color may be used to substitute, or another symbolic token to help keep track of armies. Standard equipment also includes five (originally six) dice in two colors: three red dice for the attacker, and two (originally three) white or blue dice for the defender.

Also included is a total of seventy-two Risk cards. Forty-two of these depict territories, in addition to a symbol of an infantry, cavalry, or artillery piece. One of these cards is awarded to a player at the end of each turn if the player has successfully conquered at least one territory during that turn. No more than one card may be awarded per turn. If a player collects either three cards with the same symbol, or one of each, these cards may be traded in for reinforcements at the beginning of a player's turn. These cards can also be used for game set-up (see below for details). Also included are two wild cards that depict an infantry, cavalry, and artillery piece, as opposed to one of the three and a territory. Because these cards have all three symbols, they can match with any two other cards to form a set. Twenty-eight Mission cards also come with the game to be used in the Secret Mission Risk rule variant.

In the 40th Anniversary Collector's Edition the movement route between the territories of East Africa and Middle East was removed; this was later confirmed to be a manufacturing error, an error repeated in Risk II. Subsequent editions restored the missing route.[3] While the European versions of Risk had included the variation Secret Mission Risk for some time, the U.S. version did not have this added until 1993.[4]

Each player first counts out a number of infantry for initial deployment. The number of starting armies depends on the number of players. If two are playing, then each player counts out 40 infantry, plus 40 more from a different color set. This third set is neutral and only defends if attacked (the player not attacking rolls for the neutral armies). If three are playing, each player counts out 35 infantry; four players, 30 infantry; five players, 25 infantry; six players, 20 infantry. Players then take turns claiming territories by placing an infantry on an unoccupied territory until all the territories are occupied. Players then take turns placing their remaining armies on their territories. Having done this, the actual game begins with another roll of a dice, which is used to determine the playing order.

An alternate and quicker method of setup from the original French rules is to deal out the deck of Risk cards minus the wild cards, assigning players to the territories on their cards.[2] As in a standard game, players still count out the same number of starting infantry and take turns placing their armies. The original rules from 1959 state that the entire deck of Risk cards (minus the wild cards) is dealt out, assigning players to the territories on their cards. One and only one army is placed on each territory before the game commences.

Players draft new armies and then distribute these pieces to any of their territories at the beginning of their turn. The number of armies a player may draft hinges upon three factors: number of territories owned; continent bonus(es); and redeeming Risk cards. To calculate the number of armies drafted for number of territories owned, players divide their total number of territories by three and round down to the nearest integer. If this result is less than three, round up to three armies. Players also receive bonus armies for occupying an entire continent (see table to the right). Lastly, players may receive armies for turning in a set of three Risk cards. A set may consist of the three different army units (soldier, cavalry, artillery) or be three of a kind (e.g. all three cards have cavalry pictures). If the player has five cards, the player must trade in a set. The first set to be turned is worth 4 reinforcements; the second is worth 6; third, 8; fourth, 10; fifth, 12; sixth, 15 and for every additional set thereafter 5 more armies than the previous set turned in; the number of reinforcements received is shown by a Golden Cavalry which moves along a grid every time a set is traded in. The probability of having a tradeable set of cards when holding three cards is 33.3% (9/27), 74% holding four cards (60/81), and 100% holding 5 cards (243/243).

The player places these armies on any of his territories. If a player owns one or more of the territories depicted on the set of turned in cards, the player may choose one of these territories to be awarded two additional armies that must be placed in that territory.

Example of matching up attacking (red) and defending (white) dice; in this dice roll the defender loses two armies.

When it is a player's turn to attack, the player can only attack territories that are adjacent to or connected by a sea-lane to a territory already held. A battle's outcome is decided by rolling dice. The attacking player attacks with an army, rolling up to three dice. At least one unit must remain behind in the attacking territory not involved in the attack, as a territory may never be left unoccupied. Before the attacker rolls, the defender must resist the attack with either one or two armies (using at most the number of armies currently occupying the defended territory[5]) by rolling one or two dice. Each player's highest die is compared, as is their second-highest die (if both players roll more than one). In each comparison, the highest number wins. The defender wins in the event of a tie. With each dice comparison, the loser removes one army from his territory from the game board. Any extra dice are disregarded and do not affect the results.

If an attack eliminates the final defending army within a territory, the attacker then must occupy the newly conquered territory with at least the number of attacking armies used in the last round of attack. There is no limit to the total number of additional armies that may be sent in to occupy, providing at least one army remains behind in the original attacking territory. Players may attack any number of territories any number of times before yielding the turn to the next player. Attacking is optional; a player may decline to attack at all during the turn.

If an attacker occupies a defender's last territory, the defender is eliminated from the game and the attacker acquires all of the defender's Risk cards. If the conquering player then holds five or more cards, the player must trade in sets until the player has fewer than five. The gained armies are placed immediately.

If, at the end of attacking, at least one territory was conquered that turn, the player draws a Risk card from the deck.

When finished attacking and before passing the turn over to the next player, a player has the option to maneuver any number of armies from a single territory occupied by the player into an adjacent territory occupied by the same player. This is sometimes referred to as a "free move". Under an alternate rule, the maneuvering armies may travel through as many territories to their final destination as desired, providing that all involved pass-through territories are connected and occupied by that same player. As always, at least one army must be left in the originating territory. However, the player can only distribute between two territories. Play then proceeds clockwise to the next player.

The official rulebook gives three basic strategy tips for the classic rules:

Players should control entire continents to get the bonus reinforcement armies.

Players should watch their borders for buildups of armies that could imply an upcoming attack.

Players should build up armies on their own borders for better defense.

Holding continents is the most common way to increase reinforcements. Players often attempt to gain control of Australia early in the game, since Australia is the only continent that can be successfully defended by heavily fortifying one country (either Siam or Indonesia).[6] Generally, continents with fewer borders are easier to defend as they possess fewer points that can be attacked by other players. South America has 2 access points, North America and Africa each have 3, Europe has 4, and Asia has 5.

Generally, it is thought advisable to hold Risk cards until they can be turned in for maximum reinforcements.[6] This is especially true earlier on in gameplay, because extra armies make a greater difference in the beginning of the game.[6] Eliminating a weak player who holds a large number of Risk cards is also a good strategy,[6] since players who eliminate their opponents get possession of their opponents' Risk cards. In this case, trading in Risk cards earlier may help acquire the necessary troops. If the conquering player has five or more Risk cards after taking the cards of another player, the cards must be immediately turned in for reinforcements until the player has fewer than five cards and then may continue attacking.

"Turtling" is a defensive strategy where a player who feels vulnerable tries to become too expensive to be removed while remaining a threat to harass other players. The objective of this strategy is to avoid defeat. A player using this strategy might remain in the game all the way to later stages and then mount an attack on the weakest player and start a chain elimination to remove one player after another to win the game. The player who uses this strategy is called a Turtle. The term was popularised in Real-time Strategy games where a player creates a defensive perimeter or a “Turtle Shell” around the base of operations. Solutions to counteract this strategy using cooperation have been proposed by Ehsan Honary.[7]

The rules of Risk neither endorse nor prohibit alliances or truces. Thus players often form unofficial treaties for various reasons, such as safeguarding themselves from attacks on one border while they concentrate their forces elsewhere, or eliminating a player who has grown too strong. Because these agreements are not enforceable by the rules, these agreements are often broken. Alliance making/breaking can be one of the most important elements of the game, and it adds human interaction to a decidedly probabilistic game. Some players allow trading of Risk cards, but only during their turn. This optional rule makes alliances more powerful.

Defenders always win ties when dice are rolled. This gives the defending player the advantage in "one-on-one" fights, but the attacker's ability to use more dice offsets this advantage, as indicated in the dice probability charts below. Actually capturing a territory depends on the number of attacking and defending armies and the associated probabilities can be expressed analytically using Markov chains,[8][9][10] or studied numerically using stochastic simulation.

It is always advantageous to roll the maximum number of dice, unless an attacker wishes to avoid moving men into a 'dead-end' territory, in which case he may choose to roll fewer than three.

The table below states the probabilities of all possible outcomes of one attacker dice roll and one defender dice roll. Green indicates an advantage to the attacker and red italic an advantage to the defender.

Outcome probabilities of one die roll in Risk (various numbers of dice) [11]

Defender

Attacker

one die

two dice

three dice

one
die

Defender loses one

42%

58%

66%

Attacker loses one

58%

42%

34%

two
dice

Defender loses one

25%

N/A

N/A

Attacker loses one

75%

N/A

N/A

Defender loses two

N/A

23%

37%

Attacker loses two

N/A

45%

29%

Each loses one

N/A

32%

34%

Thus when rolling three dice against two dice (the most each player can roll), three against one, or two against one, the attacker has a slight advantage, otherwise the defender has an advantage. When large armies face off, a player will tend to gain a greater advantage over his opponent by attacking rather than defending. (Multiple opponents can change the prudence of such a strategy, however.)

The following table shows the probabilities that the attacker wins a whole battle between two countries (a sequence of dice rolls). Green indicates an advantage to the attacker (i.e. that the probability to win is larger than 50%), and red italic an advantage to the defender.

Risiko! is a variant of the game released in Italy, in which the defender is allowed to roll up to three dice to defend. This variation dramatically shifts the balance of power towards defense. As shown in the following table, a defender in this variation has a 1-in-5 chance of holding a country with three defenders against eight armies in a whole battle (excluding the one that must remain behind):[15][16]

Risiko! (Italian) variation whole battle odds

Number of defenders

Chance attacker winning with equal-sized army

Number of attackers needed by desired probability of victory

>50%

>80%

>95%

3

33%

5

8

13

6

25%

10

15

22

12

17%

20

28

37

24

8%

40

52

65

48

2%

81

98

115

For comparison, under the standard rules (in which the defender may roll up to only two dice at a time) three armies would only have 1-in-19 chance of holding a country against all-out attack by eight.

This 2-player version is played according to the traditional rules of Risk. Each player takes 40 armies and alternately places one army on an unoccupied territory until each has occupied 14 territories. The remaining armies are alternately distributed on the occupied territories. The remaining 14 territories are occupied by a force called the Allied Army. These armies are composed of playing pieces different in color from those used by the two players. Two Allied Armies will be placed on each unoccupied territory for a total of 28 armies.

Each player attacks according to the traditional rules. A player may attack the other player or the Allied Army. When a player attacks the Allied Army, the other player rolls the dice for the Allied Army.

The game ends when one player loses all his territories. If the Allied Army loses all its territories, game play is continued according to the traditional rules.[17]

Each player has a "capitol" in one of the initially occupied territories. The player to capture all capitols wins. Any armies and territories that belong to the losing nation are turned over to the victor. Capitol Risk often leads to much shorter games.

Secret Mission Risk was the standard game in European editions for some decades[4] and was introduced to US editions in 1993. This form of play gives each player a specific mission short of complete world domination. Players do not reveal their missions to each other until the end of the game. The game ends when the first person to complete his mission reveals his Secret Mission card, thereby winning.[4] In 2003, a different Secret Mission version of the game was released, in which each player received four (easier) secret missions to complete.

The original missions in the 1993 US edition are:

capture Europe, Australia and one other continent

capture Europe, South America and one other continent

capture North America and Africa

capture North America and Australia

capture Asia and South America

capture Asia and Africa

capture 24 territories

capture 18 territories and occupy each with two troops

destroy all armies of a specific color or—if one's own troops are that color—capture 24 territories (one mission for each color)

Note: In the UK edition, if a player's mission is to destroy all armies of a particular color, and another player kills off the last armies of that color, their mission changes to capturing 24 territories. In the US edition, no matter who eliminates the last army, the player with the mission wins automatically[18]

In some editions, the cards display either one or two stars. Cards may be exchanged to draft a number of armies depending on the sum of these stars (limited from 2 to 10 stars) according to the table below.[19] Cards may be accumulated as long as the player wishes. The new armies are immediately deployed in any combination across the player's occupied territories.

Number of Stars exchanged

Number of Troops received

2

2

3

4

4

7

5

10

6

13

7

17

8

21

9

25

10

30

If an Objective has been accomplished on the player's turn, that player is prohibited from also drawing a Risk card on that turn. The territory on the card is irrelevant when drafting troops.

An additional card exchange regime is to offer a fixed number of armies depending on the emblem on the card. Three infantry would receive four armies, three cavalry would receive six armies, three cannons would receive eight armies, and one of each emblem would receive 10 armies.

Yet another card exchange regime follows the escalating exchange rules, but after awarding 15 armies for the sixth exchanged set the number is reset to the original four armies before increasing again with each exchange.

The official rulebook suggests variations to the gameplay mechanics for "Risk experts," any or all of which can be used depending on player preference.[5] These suggestions include:

Reducing the rate at which Risk card sets increase in value so that they only go up by 1 each time

Allowing for armies to move to any controlled territory if it has contiguity between it and its destination. (Rather than only an immediate neighbor)

Granting an attack advantage (the option to re-roll one die per battle) when attacking from or to a territory for which the attacker holds a Risk card.

Granting attackers the ability to change one of the dice rolled so that a six is showing. An attacker may do this only once per turn.

In addition to these official variations, many computer and Internet versions have different rules, and gaming clubs often use house rules or competition-adjusted rules. These may include structure such as forts, freeplay (players take turns simultaneously), or other rules.

There have been other variations of Risk, essentially "house rules," complete with titles like "Ultimate Risk" (which is played in the United States).

The following is a typical layout of the Risk game board, with a table of the corresponding continent and territory names.[20] Each territory on the typical Risk game board represents a real-life geographical or political region on Earth. As such, the territory borders are drawn to resemble the geography of those regions. This provides an interior space on which to place the army units, adds an element of realism to the game, and also adds complexity. The map is not accurate nor is it drawn to scale; New Zealand, for instance, is missing.

A representation of the Risk game board, showing the different territories, an approximation of their borders, and an approximation of their usual coloring.

The numbers in parentheses represent the number of additional armies granted during the reinforcement stage of a player's turn who controls all of the territories in that continent.

In addition to the original version of 1959, and a 40th Anniversary Edition with metal pieces, a number of official variants of Risk have been released over the years. In recent years, Hasbro has predominantly based its Risk variants on popular films. The most recent example in this trend is the Transformers version, released in June 2007. In chronological order, the variations of Risk that have been released are:

Castle Risk (1986) – A version focusing only on Europe in which each player has a castle, and the player's goal is to protect the castle from attack. Castle Risk was the first version of Risk released after 27 years of production to depart from standard play.[3] Although it was unsuccessful, it introduced many concepts integrated into later versions of Risk.[3]

Risk: 2210 A.D. (2001) – An award winning futuristic version, produced by Avalon Hill, another division of Hasbro. The game features moon territories, ocean territories and commander units and offers a number of official and unofficial expansions.

Risk Express (2006) – Designed by Reiner Knizia as part of Hasbro's Express line of games (although not as part of the US-released series). Roll different combinations of infantry, cavalry, artillery & generals to capture the territory cards.[21]

Risk: Black OPS (2008) – Limited edition released in early 2008. Print run was limited to a 1000 copies. Most of the copies were given to people in the board game industry to test out new rules for up coming editions.[citation needed]

Risk: Reinvention (2009) – Also called Risk Factor or Risk Revised Edition. This is the commercial released version of Black Ops. It features capitals, cities, missions, and very thin pieces shaped like arrows. It is also available with different components (wooden map, wooden cube pieces, etc.) as Risk Onyx Edition.[23]

Risk: Halo Wars Collector's Edition (2009) – Includes UNSC, Covenant, and The Flood. It has 42 territories and 6 sectors.

Risk 1959 (2009) – Winning Moves Games USA released a reproduction of the original game of Risk from 1959. It includes all the original graphics, wood pieces, and individual plastic storage boxes.[citation needed]

Risk: Factions (2010) – a licensed video game version of the game developed by Electronic Arts, and distributed on Xbox Live Arcade and PlayStation Network. Includes a "classic" mode which allows games played using standard original rules, and a "Factions" variation on the rules.

Risk: Metal Gear Solid (2011)

Risk Legacy (2011/12) – A game that has permanent changes to the game board and cards each time you play.

Risk Halo Legendary (2012)

Starcraft Risk (2012) – Four play modes with three different races. Each race has two unique hero units.

Many variants exist that are based on the original concept of the game of Risk and that contain much of the functionality of the original, but are not licensed by Hasbro, such as, for example, the video games Global Domination and Lux. Known as Risk clones, such variants have names not containing the term "Risk" to avoid legal issues.[24] Some of these clones are available commercially, of which many have been released through the iTunes App Store, especially for the iPad.[25] Several other Risk clones are distributed freely over the Internet, such as Dice Wars[26] and WarLight.[27] Games such as Nintendo Wars can be seen as a complex evolution which still holds some elements from Risk. NarcoGuerra is a newsgame based on the basic Risk rules, played out over a map of Mexico with the intent of educating people on the Mexican Drug War.

In addition to Risk clones, third-party products have been created which slightly modify traditional gameplay. Among the most popular third-party editions are virtual dice-rolling simulators. These can act as virtual replacements to traditional dice or be used to automatically simulate the results of large battles between territories—significantly speeding up gameplay during battles between territories with many units.

As of August, 6th 2014, Hasbro and Ubisoft have announced a new Risk game to be released in Fall 2014, on PS4 and Xbox One, as well as Xbox 360 and PS3. "Risk will feature an online league play, modern armies, and 3D battlefields. The 2010 rules are the standard set, but players can choose rule modifiers and configurable win variants." [29]

An official licensed iOS app, "RISK : The Official Game", developed for the iPhone, iPod Touch, and iPad by Electronic Arts, was released on July 16, 2010.[30] Although the iPad version (Risk HD) has to be bought separately from the iPhone version (Risk), local link up allows games to take place across versions. A maximum of 6 players can participate. If only one iOS device is available, the 'pass and play' mode allows several players to take part in a multi-player game.

Global War is a multiplayer, strategy door game for bulletin board systems, adapted from Risk. The world is divided into six continents and 42 countries. Created by Joel Bergen in 1989, It was sold in 1997 to John Dailey Software.